What The Heck … Is That Giant Mineral Dome In Thermopolis?

It looks like something from a science fiction movie. The giant mineral dome in Thermopolis is called Teepee Fountain, and it’s been growing there for nearly 115 years.

GJ
Greg Johnson

October 15, 20234 min read

Teepee Fountain in Hot Springs State Park in Wyoming is the most photographed spot in the park, says Superintendent Chris Delay.
Teepee Fountain in Hot Springs State Park in Wyoming is the most photographed spot in the park, says Superintendent Chris Delay. (Photo by Mark Fisher via geowyo.com)

It looks like something from a science fiction movie, perhaps a giant cocoon left by the pod people waiting to hatch and enslave humanity.

Truth is, that giant, multicolored dome that seems to swell up from nothing in Hot Springs State Park in Thermopolis wasn’t left by aliens and it’s not a miracle of geology that’s baffled scientists for centuries.

It’s the Teepee Fountain, and its origins are far from a mystery.

People made it.

But Why?

Underneath this large outcropping of mineral deposits is a steel pipe, first put there nearly 115 years ago to vent the area’s famous mineral hot springs.

When the mineral deposits started building up around it, a pyramid-shaped structure was built around the pipe, which over the decades has built up to form the growing dome people see today.

While it’s not a natural formation, Teepee Fountain has become a unique and popular unique draw to the area, said Chris Delay, superintendent of Hot Springs State Park.

“Oh, it’s popular,” he told Cowboy State Daily. “People take photos there daily. In fact, we’re talking about putting up a selfie stand so they can get the full fountain in it. We claim it’s the most photographed spot in the park.”

  • Teepee Fountain in Hot Springs State Park in Thermopolis, Wyoming.
    Teepee Fountain in Hot Springs State Park in Thermopolis, Wyoming. (Cowboy State Daily Staff)
  • Getting in close, you can see the lines made by the decades of mineral build-up on Teepee Fountain.
    Getting in close, you can see the lines made by the decades of mineral build-up on Teepee Fountain. (Cowboy State Daily Staff)

It’s Alive!

Because the pipe remains an active vent for the area’s famous mineral springs, it continues to grow as the minerals build up around it, Delay said.

“It was built to let steam vent from the pipes that carry the mineral water in it,” he said. “It was a 12-foot-high wooden vent, later replaced with a 25-foot steel pipe.

“Once the water cools to about 101, 102 degrees, it starts depositing the minerals out of it. And it just builds and has been growing since.”

Although he’s not sure just how thick the thing has grown, Delay said he thinks staff will start measuring its diameter each year to see how fast it’s growing.

  • Decades ago, Teepee Fountain in Hot Springs State Park was far smaller and less filled out.
    Decades ago, Teepee Fountain in Hot Springs State Park was far smaller and less filled out. (Cowboy State Daily Staff)
  • A plaque at Hot Springs State Park explains how the Teepee Fountain was formed.
    A plaque at Hot Springs State Park explains how the Teepee Fountain was formed. (Cowboy State Daily Staff)

It’s The Same Water

What’s building up around that pipe is the same as what draws thousands to the park each year to view and get into the mineral springs.

There are 27 minerals in the water, but lime and gypsum are the most prominent, Delay said.

“This water comes out of our big spring and goes down to the pipe,” he said. “It was built because at the time they were getting a lot of mineral deposits in the pipes, so the superintendent at the time thought this would keep that from happening.”

That’s not a problem anymore, however.

“Now, the purpose of (the vent) is just to keep it growing,” he added. “It’s a pretty cool feature. We love it.”

Want to know what the heck something is in Wyoming? Ask Managing Editor Greg Johnson and he’ll try to find out. Send your “What the heck is …” questions to him, along with high-quality horizontal photos of whatever it is to Greg@CowboyStateDaily.com.

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GJ

Greg Johnson

Managing Editor

Veteran Wyoming journalist Greg Johnson is managing editor for Cowboy State Daily.